Die casting machine

ABSTRACT

A die casting machine in which two die half sections are moved between a closed pouring position and an open position at which the cast piece is removed. The die half sections are mounted on a stationary and a movable base plate respectively, both of which are incorporated in a frame which can be rotated between an upstanding pouring position and a horizontal position at which the casting is removed. When in the pouring position, the die half sections are locked together by four two-piece tie rods which extend between the movable and stationary base plates and which are located at each of the corners of the die. The two sections of each tie rod are interconnected by bayonet couplings. The tie rods extend through the stationary base plate and are fixed to a platen located below the stationary base plate. The platen is connected to the stationary base plate by a parallelogram linkage and two hydraulic cylinders. After each of the bayonet couplings are engaged, the two hydraulic cylinders are actuated to move the platen away from the stationary base plate. Because of the parallelogram linkage, this motion is uniformly imparted to each of the tie rods and therefore, the closing force of the die is uniform throughout the interface of the die.

United States Patent ['19] Watry 1 DIE CASTING MACHINE Nic J. Watry, Fort Myers, Fla. I

[73] Assignee: Watry Industries Inc., Sheboygan,

' Wis.

[22] Filed: Sept. 5, 1972 [21] Appl. No.: 286,410

[75] Inventor:

[52] US. Cl 164/303, 164/341, 425/450 [51] Int. Cl 322d 17/10 [58] Field of Search 164/303, 314, 344, 341,

164/343, 137, 214, 221, 227, 323, 342; 450/DIG. 222, 450

[56] References Cited UNlTED STATES PATENTS 2,335,807 11/1943 Smith 425/D1G. 222

2,498,264 2/1950 Goldhard... 425/D1G. 222 2,744,304 5/1956 Kaul 164/303 2,976,569 3/1961 Quere 3,262,158 7/1966 Reimer 3,643,732 2/1972 Carlsen.., 164/343 X 3,667,890 6/1972 Primary Examiner-J. Spencer Overholser Assistant Examiner-John S. Brown -Rusmini 164/343 UX [451 July 16,1974

[5 7] ABSTRACT A die casting machine in which two die half sections are moved between a closed pouring position and an open position at which the cast piece is removed. The die half sections are mounted on a stationary and a movable base plate respectively, both of which are incorporated in a frame which can be rotated between an upstanding pouring position and a horizontal position at which the casting is removed. When in the pouring position, the die half sections are locked together by four two-piece tie rods which extend be- I tween the movable and stationary base plates and which are located at each of the corners'of the die.

The two sections of each tie rod are interconnected by bayonet couplings. The tie rods extend through the stationary base plate and are fixed to a platen located below the stationary base plate. The platen is connected to the stationary base plate by a parallelogram linkage and two hydraulic cylinders. After each of the bayonet couplings are engaged, the two hydraulic cylinders are actuated to move the platen away from the stationary base plate. Becauseofthe parallelogram linkage, this motion is uniformly imparted to each of the tie rods and therefore, the closing force of the die is uniform throughout the interface of the die.

5 Claims, 5 Drawing Figures DIE CASTING MACHINE BACKGROUND OF THE INVENTION the casting machine. The principal problem encountered with such machines was their inability to consistently maintain equal and adequate pressure at the interface of the two die half sections. This problem was caused by warpage or flexure of the main frame which was subjected to the extremely large forces which are required to maintain the die half sections in the closed I position.

SUMMARY OF THE INVENTION In a die casting machine embodying the present invention the die half sections are pulled together by a mechanism which exerts the closing force solely on the two base plates and thus does not subject the main frame of the machine to the substantial loads which had been experienced in the past. The linkage of the mechanism is such that it assures equal force and velocity distribution to each of the fourtie rods which extend adjacent to the four corners of the die. Thus, the mechanism assures uniform closing pressure to the entire interface of the die as well as eliminate the undesirable loads on the main frame of the machine.

DESCRIPTION OF THE DRAWINGS FIG. I is a side view of the die casting machine with the die support frame being shown'in the horizontal position and with the die half sections shown in the casting position; I

FIG. 2 is an end view taken from the left end of the machine shown in FIG. 1;

FIG. 3 is an end view taken from the right end of the machine shown in FIG. 1;

FIG. 4 is an enlarged side view of the casting ejection .linkage with portions being broken away for the sake of illustration, with the linkage being shown in a position at which the die. push out rods have been depressed; and

.FIG. 5 is an enlarged cross-sectional view of the stationary base plate and movable platen, with the interconnecting linkage being shown in a position in which the die half sections are pressed together.

DESCRIPTION OF THE PREFERRED EMBODIMENT The die casting machine embodying the present invention includes a base and a die support frame 12, which is maintained for rotation through 90 between the upstanding position and a horizontal position, as shown in FIG. 1, on rollers 12' which are fixed on each side of the base. The die support frame 12 is comprised of a main frame section 18 which supports a stationary die half section 20 and an outwardly extending frame section 22, which provides support to the movable die .half section 24. Semicircular rails 26 are provided at position.

As it is known in the die casting art, the die half sections are in a closed position when the support frame is in the upstanding position and are filled by a suitable ladle (not shown) as the die and its frame are rotated from the upstanding position to the horizontal position. After such rotation the die half sections are separated and the casting removed. Thereafter, the die half sections are again moved to the closed pouring position and are rotated to the upstandingposition for the next pouring cycle.

The stationary die half section 20 is secured to the main frame section 18 by a side bracket 30 which holds the die half section against a fixed side plate 31 and via jack bolts 32 which extend from and are fixed to the inside face of the base plate 34. The movable die half section 24 is secured to an L-shaped movable base plate 36 by a side bracket which holds the die half section 24 against one leg 37 of the base plate and by jack bolts 32' which extend from the inside face 38 of the base plate.

The movable base plate 36 is provided with rollers 40 which engage a rail 41 provided in the extending frame section 22. The movable base plate 36' is moved between the die closed position as shown in FIG. 1 and a die open position by a hydraulic cylinder 42 which. is fixed to a support arm 44 provided at the outer end of the frame section 22. The ram 42' of the cylinder is fixed to the outside face of the base plate 36. The path of the movable base plate is controlled by a guide cylinder 46.which is fixed at one of its ends to the back side of the base plate 36 and is securred in a slide bearing provided in the arm 44.

A casting ejection linkage 48 (see FIG. 4) is carried on the back sideof the movable base plate 36 and is operable to actuate ejection rods 57 which project from the back side of the movable die half section 24. The ejection linkage includes a bushing 49 which is slideably mounted on the guide cylinder 46 and four radially extending links 50 which are pivotally connected at their outer ends via links 52 to outwardly projecting lugs 54 of the base plate 36. As shown in FIG. 4, a push out plate 56 is positioned between the inside face of the movable base plate 36 and the back face of the die half section 24 and is in contact with the push out rods 57. The push out plate is connected to the links 50 via links 58 as shown in FIG. 4. As the movable base plate 36 approaches the end of its outward movement, the bushing 49 abuts against the arm 44 and, upon further outward movementof the base plate 36, the bushing slides on the guide rod 46 and thus moves towards the movable base plate 36. This movement causes the links 50 to pivot inwardly to the position shown in FIG. 4. Such motion in turn is transferred via links 58 to the push out 3 plate 56 which presses the push out rods 57 into the die half section 24 and thus eject the casting in a manner as is well known in the art.

Upon the return stroke of the movable die half section, the ejection linkage 48 is returned to its original position by a spring biased rod 59 which is fixed at one of its ends to the bushing 49 and is provided with a spring 59 which, towards the end of the inward movement of the movable base plate engages the arm 44, and upon further movement of the base plate returns the linkage 48 to its normal position, as shown in FIG. 1. This motion by the ejection linkage, of course, also retracts the push out plate 56 thereby permitting the spring biased push out rods 57 to resume their normal position.

An important feature of the present invention resides in the manner in which the two die half sections are pressed against each other so as to substantially equalize the force on the die interface. The dies are pressed together by four two-piece hold down rods 60,60 which extend between the stationary and movable base plates at the four corners of the die. Each of the twopiece hold down rods is provided with a bayonet coupling 62 which, upon axial rotation of one of the rod sections in respect to the other, locks the two rod sections together. Each of the hold down rod sections 60' is fixed to the movable base plate 36. The ends of the rod sections project through the base plate and are mounted on bearings which permit the rod sections to be axially rotated so as to permit the engagement and disengagement of the bayonet coupling. When the mold half sections have been brought to the closed position, the rodsections 60' are rotated through 45 by a hydraulic cylinder 64 which is fixed to the back side After the bayonet couplings are engaged as described I above, the two die half sections are pressed together, by two hydraulic cylinders 70 (FIGS. 3 and which are fixed to the back side of the stationary base plate 34 and whose piston 72 is fixed to a movable platen 73. The hold down rod sections 60 extend through the stationary base plate 34 and are fixed to the platen 73 by adjusting nuts 74. The movable platen is connected. to

the base plate 34 by four parallel and identical links 75, which are connected to crank arms 76 which are fixed at the ends of transversely extending shafts 77. The shafts 77 are fixed to the platen 73 by bearings 78. The corresponding crank arms 76 of the shafts 77 are connected by links 79 as shown in FIGS. 3 and 5.

As the piston 72 of cylinder 70 is extended, the platen 73 is moved away from the back face of the stationary base plate 34. During this motion the parallelogram links 75 pivot in a counterclockwise direction around their connection to the base plate 34 and the crank arms 76 rotate in a counterclockwise direction (when viewed in FIG. 5). Because links 75 are parallel and of equal length the motion imparted to each crank arm 76 is equal. In turn. because the links 79 are parallel to each other and equal in length, the motion of the platen is lineal and equal at the four corners. Thus, the force exerted by the cylinders is transmitted equally to each of the tie rods 60 and therefore the closing force at the interface of the die is uniform throughout the interface.

I claim:

I. In a die casting machine of the type having a die which is comprised of two relatively movable die half sections which may be moved relative to each other between a closed casting position, in which their inside faces are pressed together to form a die cavity, and an open position in which the half sections are separated to permit removal of the casting; a mechanism for pressing the die half sections together in a manner to substantially equalize the closing pressure throughout the interface of the die; said mechanism comprising:

a plurality of tie down rod means extending along opposite sides of the die and in a direction generally transverse to the interface of the die; each of said tie down rod means being fixed at one of its ends to one of said half sections when the die is in the casting position and at the other of its ends being fixed to a movable platen which extends along the outside face of the other of said half sections;

linkage means connecting said movable platen to said other of said half sections for uniform movement of said platen in respect to said other of said half sections; and

force exerting means interposed between said other of said half sections and said movable platen; said force exerting means being operable to move said platen in respect to said other of said die half sections when said die half sections are in the casting position; and said linkage means providing equal and simultaneous movement to said platen and said tie down means connected thereto to thereby cause each of said tie down means to exert equal amounts of die closing force to said die half sections;

each of said tie down rod means being comprised of a two-section tie down rod which is fixed at one of its ends to said one die half section and at its other end to said movable platen; andsaid sections of each of said tie down rod being connected by disconnectable coupling means, which, upon disconnection, permits said die half sections to be moved to the open position and, upon connection, permit said die half sections to be pressed in the casting position by said force exerting means; and

each of said coupling means being a bayonet coupling, and the die casting machine including motor means for axially rotating one of the sections of each of said two section tie rods in respect to the other section to thereby move said bayonet couplings between the engaging and disengaging positions.

2. A die casting machine according to claim 1 wherein said linkage means is a parallelogram linkage, the links of which are pivotally connected at one of their ends to said other of said half sections and are pivotally connected at the other of their ends to said movable platen.

3. In a die casting machine of the type having a die which is comprised of two relatively movable die half sections which may be movedrelative to each other between a closed casting position, in which their inside faces are pressed together to form a die cavity, and an open position in which the half sections are separated to permit removal of the casting; a mechanism for pressing the die half sections together in a manner to substantially equalize the closing pressure throughout the interface of the die; said mechanism comprising:

a plurality of tie down rod means extending along opposite sides of the die and in a direction generally transverse to the interface of the die; each of said tie down rod means being fixed at one of its ends to one of said half sections when the die is in the casting position and at the other'of its ends being fixed to a movable platen which extends along the outside face of the other of said half sections;

linkage means connecting said movable platen to said other of said half sections for uniform movement of said platen in respect to said other of said half sections; and

force exerting means interposed between said other of said half sections and said movable platen; said force exerting means being operable to move said platen in respect to said other of said die half sections when said die half sections are in the casting position; and said linkage means providing equal and simultaneous movement to said platen and said tie down means connected thereto to thereby cause each of said tie down means to exert equal amounts of die closing force to said die half sections;

said linkage means being comprised of a plurality of parallel links of equal length which are pivotally connected at one of their ends to said other movable half section, the other end of each of said links being connected to a separate crank arm which is pivotally fixed to said movable platen, and said crank arms being connected to each other by connecting link means which limit the motion of said crank arms to simultaneous and equal pivotal movement in respect to said movable platen.

4. In a die casting machine of the type having a die which is comprised of two relatively movable die half sections which may be moved relative to each other between a closed casting position, in which their inside faces are pressed together to form a die cavity, and an open position in which the half sections are separated to permit removal of the casting; a mechanism for pressing the die half sections together in a manner to substantially equalize the closing pressure throughout the interface of the die; said mechanism comprising:

a plurality of tie down rod means extending along opposite sides of the die and in a direction generally transverse to the interface of the die; each of said tie down rod means being fixed at one of its ends to one of said half sections when the die is in the casting position and at the other of its ends being fixed to a movable platen which extends along the outside face of the other of said half sections;

linkage means connecting said movable platen to said other of said half sections for uniform movement of said platen in respect to said other of said half sections; and

force exerting means interposed between said other of said half sections and said movable platen; said force exerting means being operable to move said platen in respect to said other of said die half sections when said die half sections are in the casting position; and said linkage means providing equal and simultaneous movement to said platen and said tie down means connected thereto to thereby cause each of said tie down means to exert equal amounts of die closing force to said die half sections;

said tie down'rod means being comprised of four parallel tie down rods which extend in planes on opposite sides of the die; and

said linkage means including two pairs of equal length and parallel links which are pivotally connected at one of their ends to said other of said half sections; the links of each of said pairs being connected to a corresponding pair of equal length crank arms, the crank arms of each pair being fixed to opposing ends of separate shafts which are fixed for axial rotation to said movable platen and are in parallel relationship to each other; and the corresponding crank arms of each shaft being connected by parallel and equal length links.

5. A die casting machine according to claim 4 wherein each of said tie down rods is comprised of two sections one of which is fixed at one of its ends to said one half section and the other of which is fixed at one of its ends to said movable platen; and wherein each of said sections of each of said tie down rods includes bayonet coupling means to permit connection and disconnection of said sections upon axial rotation of one tie down rod section in respect to the other. 

1. In a die casting machine of the type having a die which is comprised of two relatively movable die half sections which may be moved relative to each other between a closed casting position, in which their inside faces are pressed together to form a die cavity, and an open position in which the half sections are separated to permit removal of the casting; a mechanism for pressing the die half sections together in a manner to substantially equalize the closing pressure throughout the interface of the die; said mechanism comprising: a plurality of tie down rod means extending along opposite sides of the die and in a direction generally transverse to the interface of the die; each of said tie down rod means being fixed at one of its ends to one of said half sections when the die is in the casting position and at the other of its ends being fixed to a movable platen which extends along the outside face of the other of said half sections; linkage means connecting said movable platen to said other of said half sections for uniform movement of said platen in respect to said other of said half sections; and force exerting means interposed between said other of said half sections and said movable platen; said force exerting means being operable to move said platen in respect to said other of said die half sections when said die half sections are in the casting position; and said linkage means providing equal and simultaneous movement to said platen and said tie down means connected thereto to thereby cause each of said tie down means to exert equal amounts of die closing force to said die half sections; each of said tie down rod means being comprised of a two-section tie down rod which is fixed at one of its ends to said one die half section and at its other end to said movable platen; and said sections of each of said tie down rod being connected by disconnectable coupling means, which, upon disconnection, permits said die half sections to be moved to the open position and, upon connection, permit said die half sections to be pressed in the casting position by said force exerting means; and each of said coupling means being a bayonet coupling, and the die casting machine including motor means for axially rotating one of the sections of each of said two section tie rods in respect to the other section to thereby move said bayonet couplings between the engaging and disengaging positions.
 2. A die casting machine according to claim 1 wherein said linkage means is a parallelogram linkage, the links of which are pivotally connected at one of their ends to said other of said half sections and are pivotally connected at the other of their ends to said movable platen.
 3. In a die casting machine of the type having a die which is comprised of two relatively movable die half sections which may be moved relative to each other between a closed casting position, in which their inside faces are pressed together to form a die cavity, and an open position in which the half sections are separated to permit removal of the casting; a mechanism for pressing the die half sections together in a manner to substantially equalize the closing pressure throughout the interface of the die; said mechanism comprising: a plurality of tie down rod means extending along opposite sides of the die and in a direction generally transverse to the interface of the die; each of said tie down rod means being fixed at one of its ends to one of said half sections when the die is in the casting position and at the other of its ends being fixed to a movable platen which extends along the outside face of the other of said half sections; linkage means connecting said movable platen to said other of said half sections for uniform movement of said platen in respect to said other of said half sections; and force exerting means interposed betwEen said other of said half sections and said movable platen; said force exerting means being operable to move said platen in respect to said other of said die half sections when said die half sections are in the casting position; and said linkage means providing equal and simultaneous movement to said platen and said tie down means connected thereto to thereby cause each of said tie down means to exert equal amounts of die closing force to said die half sections; said linkage means being comprised of a plurality of parallel links of equal length which are pivotally connected at one of their ends to said other movable half section, the other end of each of said links being connected to a separate crank arm which is pivotally fixed to said movable platen, and said crank arms being connected to each other by connecting link means which limit the motion of said crank arms to simultaneous and equal pivotal movement in respect to said movable platen.
 4. In a die casting machine of the type having a die which is comprised of two relatively movable die half sections which may be moved relative to each other between a closed casting position, in which their inside faces are pressed together to form a die cavity, and an open position in which the half sections are separated to permit removal of the casting; a mechanism for pressing the die half sections together in a manner to substantially equalize the closing pressure throughout the interface of the die; said mechanism comprising: a plurality of tie down rod means extending along opposite sides of the die and in a direction generally transverse to the interface of the die; each of said tie down rod means being fixed at one of its ends to one of said half sections when the die is in the casting position and at the other of its ends being fixed to a movable platen which extends along the outside face of the other of said half sections; linkage means connecting said movable platen to said other of said half sections for uniform movement of said platen in respect to said other of said half sections; and force exerting means interposed between said other of said half sections and said movable platen; said force exerting means being operable to move said platen in respect to said other of said die half sections when said die half sections are in the casting position; and said linkage means providing equal and simultaneous movement to said platen and said tie down means connected thereto to thereby cause each of said tie down means to exert equal amounts of die closing force to said die half sections; said tie down rod means being comprised of four parallel tie down rods which extend in planes on opposite sides of the die; and said linkage means including two pairs of equal length and parallel links which are pivotally connected at one of their ends to said other of said half sections; the links of each of said pairs being connected to a corresponding pair of equal length crank arms, the crank arms of each pair being fixed to opposing ends of separate shafts which are fixed for axial rotation to said movable platen and are in parallel relationship to each other; and the corresponding crank arms of each shaft being connected by parallel and equal length links.
 5. A die casting machine according to claim 4 wherein each of said tie down rods is comprised of two sections one of which is fixed at one of its ends to said one half section and the other of which is fixed at one of its ends to said movable platen; and wherein each of said sections of each of said tie down rods includes bayonet coupling means to permit connection and disconnection of said sections upon axial rotation of one tie down rod section in respect to the other. 